Very cool, who's hosting this wiki? I guess this is not evil like similar services that have come before because it's open source and anybody can host a Wikalong and it doesn't deface the page it's wikiing about since it's a sidebar! Is that right?
Wikalong is a FirefoxExtension that embeds a wiki in the SideBar of your browser, indexed off the url of your current page. It is probably most simply described as a wiki-margin for the internet. One general difference in the functioning of the wiki you may find is that wiki links would be external, as opposed to traditional wikis which are more internal link centric.